Protect trees from summer storm damage

July 17, 2012

Many trees fell victim to the recent derecho winds.

Recent storms wreaked havoc upon trees across a wide swath of Virginia and other eastern states. While there is little landowners can do to avoid damage from a 70 to 80 mph wind, thoughtful planting and routine maintenance can go a long way toward protecting your trees from the average storm, says Virginia Tech College of Natural Resources and Environment Associate Professor and Extension Specialist Eric Wiseman.

Property owners should be discriminating when planting or retaining trees on their property. Most oaks are “well-behaved,” Wiseman notes. They are slow-growing trees known for strong wood, with less tendency to develop co-dominant leaders, an unstable condition of multiple main trunks. Besides oaks, Wiseman recommends hickory, fruitless sweetgum, beech, and blackgum as storm-tolerant lawn trees.

He advises against landscape plantings of silver maples, willows, ashes, white pines, and loblolly pines, as well as the notoriously fracture-prone Bradford pear. These faster growing trees tend to be weak-wooded and decay-prone, he explains.

Even the right tree can be easily uprooted if not planted properly. Selecting a tree with a well-developed root system and planting it at the correct depth is crucial to the tree’s longevity.

“You get what you pay for,” he warns, “so buy your tree from a reputable nursery.”

Trees need routine maintenance, particularly during their “adolescent years,” Wiseman says. Periodic pruning improves a tree’s structure by removing dead and defective branches, such as multiple leaders or trunks and weak branch attachments with embedded bark. Both of these conditions make trees susceptible to storm damage.

Topping, or indiscriminate reduction of tree height, is not an appropriate pruning practice. In fact, topping will likely weaken the tree in the long run. When pruning alone cannot remedy a structural issue, a professional tree service can sometimes install cables or bracing to support weak branches.

Signs that a tree is in trouble include cracks, cavities, decay, dead limbs, and sometimes mushrooms at its base. Recent excavation beneath the tree damages its roots, which in turn weakens the tree, increasing its susceptibility to decay, pests, and wind damage.

Wiseman recommends calling in an arborist for evaluation and tasks related to tree health and safety. The person who cuts your grass and trims your shrubs may give tree advice, but may not have an arboriculture (tree care) background. An arborist can detect the signs and has tools to help with the detection of root problems.

“Some landscapers are also arborists, but most aren’t,” Wiseman says. “Virginia has no certification requirement for arborists, so look for someone certified by the International Society of Arborists. Tree service companies accredited by the Tree Care Industry Association are also well qualified.”

Even the best trees are put to test during high derecho winds like those experienced June 29. Under these conditions, it’s impossible to absolutely avoid tree problems.

“The only thing you can do to eliminate tree problems is to get rid of all trees, but that’s not a good idea,” Wiseman says. “Trees reduce cooling and heating costs in homes, mitigate air pollution, protect water quality, and have aesthetic value.”